A micro valve device belongs to a key device in microfluidic control, and has important applications in fields such as biology, medical care and refrigeration. The micro valve device based on a micro-electromechanical system (MEMS) technology has advantages such as accurate control, low cost, mass production, good stability and reliability, etc.
In fluid control, the micro valve device may be used as a pilot valve for controlling a main valve, to achieve accurate control of an opening degree of the main valve, so as to reach a purpose of controlling fluid flow.
Chinese Patent Application No. 200580011090.3 and No. 200780046457.4, and U.S. Pat. Nos. 6,523,560, 7,011,378 and 6,761,420 disclose a micro valve device which can be used as a pilot valve, wherein only one fluid port is connected with a main valve. In a process that the pilot valve controls the main valve to achieve fluid control, a standard reference pressure must be provided, and opening and closing or a flow rate of a main fluid is controlled based on a relationship between a control port output pressure of the pilot valve and a standard reference pressure.
The standard reference pressure, as an absolute pressure value, is usually provided by an external of the micro valve device, for example, the standard reference pressure is often generated by using a mechanism such as a spring in an actual product. However, such a mechanism may cause phenomena such as aging and failure, so that deviation and even failure will occur to the standard reference pressure.